Warning: Cannot modify header information - headers already sent by (output started at /home/sites/site65/users/yann/web/Solutions/Nabopoll/admin/install.php:16) in /home/sites/site65/users/yann/web/Solutions/Nabopoll/admin/admin.inc.php on line 13

What can I do ?
In another topic I saw it was recommended to execute first a .sql , but how one does that (sorry completely newbie in all these matters)

Warning: Cannot modify header information - headers already sent by (output started at /home/sites/site65/users/yann/web/Solutions/Nabopoll/admin/install.php:16) in /home/sites/site65/users/yann/web/Solutions/Nabopoll/admin/admin.inc.php on line 13

What can I do ?In another topic I saw it was recommended to execute first a .sql , but how one does that (sorry completely newbie in all these matters)